The opening of the Broadway musical Spider-Man: Turn Off The Dark has been pushed back two weeks as the creative team scrambles to get through dress rehearsals and meet safety standards for the performers. Directed by Julie Taymor and featuring original songs by U2’s Bono and The Edge, Spider-Man: Turn Off The Dark has been in development for over three years with a budget that has swelled to an eye-popping $60 million.

Spider-Manwas scheduled to begin previews on November 14 and open on December 21, but it will now open in January and begin previews sometime late this month. Two actors were recently injured during rehearsals of the shows complex flying maneuvers, leading the New York Department of Labor to open an investigation into the safety of on-set working conditions. Until they are satisfied with the safety of the flying sequences the play can’t open.

According to the New York Post, the cast has rehearsed all of the individual scenes—but they have yet to perform the musical straight through. “We’re less than two weeks away, and we have no idea what the running time is going to be,” a source told the Post. Adding to producers’ concerns are reports that the play has only sold $8 million in advance tickets. While that would be a healthy figure for most productions, the massive budget for Spider-Man requires the show to be a mega-blockbuster if its backers simply want to break even.